This is the 17th year of participation by the Department of Pediatrics, Baylor College of Medicine, in the Southwest Oncology Group (formerly the Southwest Cancer Chemotherapy Study Group). The purposes of this cooperative group are to better understand the etiology, epidemiology, and pathogenesis of cancer in children and to develop better methods for the control or care of cancer in children by a multidisciplinary approach. Activities include: Phase I studies of new chemical or biological agents; Phase II trials of new agents or combinations of agents with other therapeutic measures against various malignant diseases; Phase III trials of various treatment regimens to determine the best modalities of care. Newer interests of the group have included immunological studies of these diseases in preparation for possible immunotherapy. The concept of the group has been broadened to include the direct participation of radiotherapists and surgeons in all appropriate group activities.